急！如何在jsp中实现把大图片转换成小图片？

import com.sun.image.codec.jpeg.*;
import java.awt.image.*;
import java.awt.*;
import java.net.*;
import java.applet.*;
import java.io.*;
import java.util.*;......
                        //------------生成缩略图------------------//
                        BufferedImage image;
                        Image img=null;
                        Toolkit tk=Toolkit.getDefaultToolkit();
                        Applet app=new Applet();
                        MediaTracker mt = new MediaTracker(app);
                        img=tk.getImage(request.getRealPath("")+"\\uploadfile\\"+fileName);//获取原始图
                        mt.addImage(img, 0);
                        mt.waitForID(0);
                        double rate1=((double)img.getWidth(null))/120.0+0.1;
                        double rate2=((double)img.getHeight(null))/120.0+0.1;
                        double rate=rate1>rate2?rate1:rate2;
                        int new_w=(int)(((double)img.getWidth(null))/rate);
                        int new_h=(int)(((double)img.getHeight(null))/rate);
                        BufferedImage buffImg = new BufferedImage(new_w,new_h,BufferedImage.TYPE_INT_RGB);
                        Graphics g = buffImg.createGraphics();
                        g.setColor(Color.white);
                        g.fillRect(0,0,new_w,new_h);
                        g.drawImage(img,0,0,new_w,new_h,null);//绘制缩略图
                        g.dispose();
                        java.io.OutputStream tempout=null;
                        java.io.File tempfile=new java.io.File(request.getRealPath("")+"\\uploadfile\\"+fileName+"_small.jpg");
                        tempout= new FileOutputStream(tempfile);
                        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(tempout);
                        encoder.encode(buffImg);
                        if(tempout!=null)tempout.close();
                        //------------缩略图生成完毕----------------//
......